Sure.
I have browsed many...many forums etc and this occurs only here. So, we can confirm some association.
Antivirus kits
Home - Avira (using IE8)
Work - Mcafee (using Firefox)
Both machines are using Windows XP with the latest service packs etc making them fully upto date.
I don't get much facetime with my home PC so a full scan is planned just not executed yet. I can't self-scan my work based PC but this is done every night by automatic IT executable and I have not been notified of anything amiss.
I now use the Tabs functions more to help prevent this annoyance. Always having two tabs active means that when this occurs it occurs on only one tab so I just manually close that tab (it displays another fake warning which I "X" close down rather than using its "OK" to close).
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